Some owners have had good success restoring old cracked and stained
leather seats using Leatherique. Takes a few days to soften the old
leather, redye it to original color and finish its top surface.
www.*leatherique*.com

Door lock question. Vacuum powered door locks open and close ALL doors,
trunk and fuel door. One could, I suppose, cripple the vacuum system at
the driver's door lock so the other doors no longer locked or unlocked
in tandem with the driver's door.

Back windows do have a lock out (center) button on the driver's window
button console.

Good luck with your "new" car.